The present invention relates to an arm device for an industrial robot used for welding or assembly operations. More particularly, the invention relates to an arm device for an industrial robot which is prevented from being damaged by impact if it strikes an obstacle.
Heretofore, there have been provided industrial robot devices, as disclosed in, for example, Japanese Laid-Open Patent Publication No. 160094/83, whose robot arms are allowed to freely rotate in at least one of horizontal and vertical directions when an excessive torque is exerted thereon so as to prevent extraordinary external forces from being applied to the operating mechanism of the arm.
However, such conventional devices have a large and complicated structure, and therefore, disadvantageously, a high manufacturing cost since mechanisms for allowing movement in both in horizontal and vertical directions have to be arranged in different positions.